Secondary throttle dampening device



July 4, 1961 Filed on. 23, 1958 T. F. CRAMER SECONDARY THROTTLE DAMPENING DEVICE 2 Sheets-Sheet 1 R INVENTOR. T HOMAS F. CRAMER ATTORNEYS y 1961 "r. F. CRAMER 2,990,821

SECONDARY THROTTLE DAMPENING DEVICE Filed Oct. 23, 1958 2 Sheets-Sheet 2 /6 Z win/r5 170/66 MAN/F060 /l m I V INVENTOR.

Q THOMAS F- CRAMER BY g t 10 ATTORNEYS nited States Patent Ofice Patented July 4, 1961 2,990,821 SECONDARY THROTTLE DALMPENING DEVICE ThomasF. 'Cramer, Warren, Mich., assignor to Holley I Carburetor Company, Van Dyke, Mich., a corporation of Michigan Filed Oct. 23, 1958, Ser. No. 769,119

16 'Claims. (Cl. 123-103) This invention pertains to a selective dampening device and more particularly to a dampening device for use with a secondary throttle plate in an internal combustion engine multiple stage carburetion system.

A multiple stage carburetion system comprises an operator-controlled primary throttle plate assembly and a venturi-vacuum controlled secondary throttle plate assembly which is operable to supply additional fuel mixture flow to the combustion chambers at high speeds.

In engines having governing systems wherein at governed speed the primary throttle plate is automatically adjusted to restrict the fuel mixture flow to the combustion chambers, the subsequent movement of venturi-operated secondary plate is delayed and very quick, causing a compensating opening of the primary plate. The secondary plate in turn opens slightly due to the increased flow through the primary venturi and repeated alternate adjustments or hunting of the primary and secondary plates result. This invention successfully prevents hunting by applying a dampening or resisting movement to the secondary plate so that its initial closing after governing is modified and subsequent changing of the primary throttle plate is substantially eliminated.

FIG. 2 is a side elevational view, with portions thereof in cross section, taken on the plane of line 22 of FIG. 1 and looking in the direction of the arrows;

FIG. 3 is a bottom plan view taken on the plane of line 3--3 of FIG. 1 and looking in the direction of the arrows; and Y I FIG. 4 is a sectional view taken along the line 44 of FIG. 3.

Referring now to FIG. 1, a four-barrel carburetor 10, of the type referred to above and having an air intake 12, is sectioned to expose one of the primary barrels 14 and one of the secondary barrels '16. The primary barrel 14 is provided with a restriction or venturi throat 18 and a conventionally operated throttle plate 20 mounted on the shaft 22 which extends through the other primary barrel in which is mounted a throttle plate identical This invention provides a dampening device for a secondaryrthrottle actuating arm which comprises a piston reciprocable in a tubular element which is supported for reciprocal'movement in a cylinder. Movement of the piston in the element will cause fluid to-flow from one cylinsponseto-an engine vacuum .source and has openings therein which, according to the vacuum conditions, register with one or the other of the passages. One passage is restricted so that pistonmovement is correspondingly restricted and'the other passage is sufiiciently large so that the piston is freely movable.

i The piston is preferably connected to an extension of the secondary throttle actuating arm so that when its movement is. controlledor restricted, the secondary arm movement'will be likewise controlled.

It-isftherefore an objectof this invention to provide adampening. device for a multiple-stage carburetor secondaryflhrottle movement during governing action by, a devicewhich selectsone of a multiplicity of passages of varying'restriction' for fluid to flow in .a closed cylinder during piston travel in said cylinder. H ..I.t is another object of this invention to provide dampeningme'answhich comprise a piston operable in a closed cylinder with piston trayel causing fluid to be pumped from one cylinder end to the other and means to select one .of. a number of fluid passages ofvaried restriction to correspondingly control the movement of the piston rela- .tive the cylinder.

to plate 20. The secondary barrel 16 is also provided with a venturi throat 24 and a throttle plate 26 mounted on the shaft 28 which extends through the other secondary barrel in which is mounted another secondary plate. 7 While a particular four-barrel carburetor is shown for purposes of illustration,'it will be apparent that the invention is equally applicable to two-barrel or other multi-stage carburetors.

A vacuum device 30, commonly referred to as a gover-. nor diaphragm assembly, is mounted on the boss 32 ex tending from the carburetor throttle body 34. The assembly 30 includes a body 36 formed to provide recesses 38 and 40. The recess 40 is covered by means of a flexible diaphragm 42 which is secured to the body36 by means of a cover member 44 formed to provide an air tight chamber 46 of which the flexible diaphragm 42 forms a wall. The cover member may be secured by any suitable means such as screws 47.

As shown by FIGS. 1 and 2, the diaphragm'42 has secured to the center thereof in the conventional manner a rod "48 passing through passage 50 in the body 36 and having a laterally extending end 52 pivotally' secured to the lever 54 which is rigidly secured to the end. 56 of the primary throttle shaft 22 extending into the chamber 3 8. The shaft 22 is mounted in an anti-friction bearing 39, and a spring 41 is disposed between the bearing 39 and the steel and .leather washers 43 and A5 to proyide a seal. A tension spring 58 attached between thefad justable pin 60, mounted inone of the holes 62. inthe body 36., and the fixed pin .64, secured to the lever 54, tends to hold the primary throttle plate 20 in theopen position. An atmospherically vented. cover plate 66 may be' secured by screws 68 to housing 36, thereby protecting the mechanism within chamber 38.

- The orifice 72 at the primary venturi throat 18 and the orifice 74 below the primary throttle plate .20 are con nected by means of the passages 76 and 7-8 having fixed restrictions 80 and 82respectively with the passage 84 in the body member 3 6 and the passage 86 in the cover member 44 which lead to the chamber 46. A passage 88 when. a; preferred embodiment of this invention is described i i-detail andwhichis illustrated in the drawings,

connecting with passage '84 terminates in an. opening the body 36 adapted to receive a threaded fitting 90.

Located at any desired position on'the engine is a. gov ernor valve assembly 92 comprising a stationary housing 94 adapted to be mounted on the engine and containing a shaft 96 driven in any suitable manner in proportion to engine or vehicle speed. Mounted for rotation with the shaft 96 is. a laterally extending, sleeve 98 having a spring 100 mounted within theaxial passage 102.. in th e sleeve by attachment at one end to the internallyth readed member 104, which is keyed in passage102, Spring is adjustable axially of sleeve 98 byt'ur ning'thel adjust ment screw 106 which is reached by removing I screw The other end of thejspring'jl0 0 i s'secur d the governor weight 110 inovablef.Qaxi'ally wit chamber 112 against the spring 100 and having at the free end thereof a valve 114 adapted to close the orifice 116 when the weight 110 is forced outwardly due to the rotation ofthe shaft 96 and the sleeve 98 in accordance with engine speed. The engine or vehicle speed at which the orifice 116j'will' be closed is dependent, of course, upon theadjustment of the spring 100. It is, apparent, also, that. some other governor valve structure may be employed.

. A vacuum balancing air bleed is provided through assembly 92 to chamber 46 when orifice 116 is uncovered. Conduit 118 between the air intake 12 of the carburetor and the housing 94 and conduit 122 between the housing 94 and the passage, 88 in the body 36 are provided so that whenthe engine or vehicle is operating at a speed insuflicient to close the orifice 116, engine vacuum will draw clean air through the conduit 118, into the housing 94, through the orifice 116 and into the chamber 112, through the passage 102 and the axial passage 120 in the shaft 96 and thence through the conduit 122 to the governor diaphragm assembly 30. When the engine reaches governed speed, the orifice 116 is closed and the air bleed through conduit 122 is cut off. When this occurs vacuum in the chamber 46 urgesthe diaphragm 4 2 downwardly, as in FIG. 2, against the spring 58 to close the primary throttle plates 20..

A secondary throttle diaphragm assembly 124 is mountedat the opposite side of the throttle body 34. This assembly comprises a body 126 having a recess 128 vented to the atmosphere through a plate 130' secured by screw 132 and a recess 134 closed by a flexible diaphragm 136 which is secured to the vbody 126 by means of a cover 138 formed to provideoppositely disposed chambers 140 and 142 between which the flexible diaphragm 136 forms a movable wall. A housing 143 depends from cover 138 and contains means, later described, for selectively dampening rod 146. The chamber 142 contains a compression spring 144 positioned between the cover 138 and the rod 146, which is secured to the center of the diaphragm 136, so that the spring 144 urges the rod 146 upwardly to rotate the lever 148 secured rigidly to the secondary throttle shaft 28 counterclockwise, as in FIG. 3, and close the secondary throttle plates 26. A conduit 150 extending between the chamber 142 and the vacuum passages 152 and 154 opening to the primary and secondary venturi throats 18 and 24 enables primary and/ or secondary venturi vacuum to evacuate the chamber 142 anddisplace the diaphragm 136 downwardly, as in FIG. 1,, againstthe spring 144 to open the secondary throttle 26. The force of the spring 144 is selected so that the secondary throttle plate 26 will be open at any predetermined venturi vacuum.

In the structure described above, proper governing action depends upon the particular closing of the throttle plates 20 and 26 when the engine or vehicle has reached a predetermined governing speed so as to diminish or cut 011 the flow of motive fluid to the engine. However, in the caseof dual carburetion as described above, the automatic closing of the secondary. throttle plates 26 lags behind that of the primary throttle plates 20, particularly at governed engine speeds at which the secondary plates 26 are not fully open so that any linkage (not shown) usually etfective to positively close the secondary plates 26 with the primary plates 20 does not come into operation. While this is tolerable in the normal function of the dual carburetor, e.g. during acceleration, it is highly objectionable for the purposes of governing. This causes hunting, since the primary throttle plates have to first close farther than would otherwise be required to compensate for the open secondary plate and then open when the secondary. plates finally close.

In order to remedy this situation a dampening device is-providedas shown in FIGS. 3 and 4. This device comprises housing 143 which depends from cover 138 and contains a fluid filled control cylinder 160 which has 2,990,821 e Y a a p a i formed in the walls thereof vertical passages 162, 164 which are capable of providing passage for fluid, such as oil, between the cylinder top and bottom with passage 164 being more restricted than passage 162. Slidably supported in cylinder is tubular element 166 which has an open top and circumferentially spaced openings 168, 170- near the bottom which are registrable respectively with the lower intersections of passages 162, 164 with the wall of cylinder 160. Slidable in element 166 is piston 172 which is attached to and movable with an extension of secondary throttle arm 146. Connector 174 has a leg fixed to the bottom of element 166 and a second leg fixed to spring-urged piston 176 which is reciprocable in a cylinder 178. Cylinder 178 is formed in housing 143 and is connected to an engine vacuum such as manifold vacuum or governor vacuum through pas-.. sage 180.

During normal or ungoverned carburetor action, the movement of arm 146 is substantially unrestricted by the control device since element 166 is in its downward position, as shown in FIG. 4, and fluid fiows between the upper and lower endsof cylinder 160 on movement of piston 172 through the large passage 162. However, at governed speeds when the vacuum increases in passage 180, piston 176 and attached tubular element 166 are moved upwardly until passage 162 is closed and opening 170 registers with passage 164 providing a restricted path for fluid flow between cylinder ends. This will slow the movement of piston 172 and will correspondingly control the movement of arm 146 and secondary throttle plates 26 to prevent the surge or quickened throttle movement and resultant hunting.

While either manifold or governor vacuum may be connected to passage 180 it has been found that governor vacuum is less sensitive to small changes in engine conditions and therefore very desirable. Of course, the control device may be actuated by other suitable means responsive to governing action.

If desired, of course, all or any part of the structure shown herein may be incorporated into a single, compact carburetor unit adapted for placement in a vehicle engine compartment.

The drawings and the foregoing specification constitute a description of the improved secondary throttle dampening device in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. In an internal combustion engine having governing means, a carburetor having a throttle barrel with a throttle plate pivotally mounted therein, a governing system to actuate said throttle plate to a governed position at governed speed, a piston operable in a tubular element, a cylinder supporting said tubular element for relative movement therewith, a plurality of passages having different resistances to fluid flow formed in the cylinder body with each passage intersecting the cylinder wall on either side of piston travel, said tubular element having openings in the wall thereof registrable with said intersections in the cylinder wall to establish a communication between opposite piston sides through one of said passages, said tubular element adjustable in response to engine governing conditions relative said cylinder for establishing communication of certain of said passages with certain of said openings with difierent communications ofiering different resistances to fluid flow, means for adjusting said element relative said cylinder for selecting a particular fluid resistance path and for retarding piston speed, one-of said cylinder and piston being connected to said throttle plate for correspondingly retarding the movementof said throttle plate under said engine governing conditions.

2. A multi-stage carburetor having primary and second ary throttle barrels, throttle plates being mounted in said moat tubular element for relative movement therewith, a plural-- ity of passages having difierent resistances to fluid flow formed in the cylinder body with each passage intersecting the cylinder wall on either end of piston travel, said tubular element having openings in the wall thereof registrable with said intersections in the cylinder wall to establish a communication between opposite piston ends through one of said-passages, said tubular element adjustable relative said cylinder for establishing communication of certain of said passages with certain of said openings with different communications offering difierent resistances to fluid flow, piston means responsive to engine governing conditions for adjusting said element relative said cylinder for selecting a particular fluid resistance path and'for retarding piston speed, one of said cylinder and piston being connected to said actuating means for. correspondingly retarding the movement of said secondary throttle under said governing conditions.

3. In an internal combustion engine having governing means, a multistage carburetor having primary and secondary throttle barrels, throttle means pivotally mounted in each of said barrels, a governing system to for actuating said primary spacedopenings formed therein with an opening r'egis-l trable with each of said passage means, said movable' element being responsive to an engine vacuum condition. for selecting one of said passage means having a restricted fluid flow for dampening the movement between said members and said throttle.

71A carburetor having a throttle barrel with a throttle pivotally mounted therein, a closed fluid container member, a wall member movable relative to said containermember, a plurality of passage means having different resistances to fluid flow formed in the wall of said container member for movement of fluid between oppo site sides of said wall member during relative movement between said wall member and said container member,

. element being responsive to manifold vacuum for selectactuate said throttle means to a governed position at governed speed, a piston operable in a closed fluid containing cylinder, a multiplicity of passage means for fluid movement from one end of piston travel to the other during piston movement in the cylinder, said passage means having diflerent resistances to fluid flow, one of said piston and cylinder being connected to the secondary throttle means, selective means responsive to engine governing conditions for selecting one of said passage means having a restricted fluid flow for dampening the movement between said piston and cylinder and said secondary throttle means.

4. A carburetor having a throttle barrel with a throttle pivotally mounted therein, a closed fluid container member, a wall member movable relative to said container member, a plurality of passage means having diflerent resistances to fluid flow formed in one of said members for movement of fluid between opposite sides of said wall member during relative movement between said wall member and said container member, means connecting said throttle to one of said members, and selective means which is responsive to an engine vacuum condition for selecting one of said passage means having a restricted fluid flow for dampening the movement between said members and said throttle.

5. A carburetor having a throttle barrel with a throttle pivotally mounted therein, a closed fluid container member, a wall member movable relative to said container member, a plurality of passage means having diflerent resistances to fluid flow formed in the wall of said container member for movement of fluid between opposite sides of said wall member during relative movement be tween said wall member and said container member, means connecting said throttle to one of said members, and selective means which is responsive to an engine vacuum condition for selecting one of said passage means having a restricted fluid flow for dampening the movement-between said members and said throttle.

6. A carburetor having a throttle barrel with a throttle pivotally mounted therein, a closed fluid container member, a wall member movable relative to said container member, a plurality of passage means having diflerent resistances to fluid flow formed in the wall of said container member for movement of fluid between opposite sides of said wall member during relative movement between said wall member and said container member, means connecting said throttle to one of said members, and a movable element in said container member having ing one of said passage means having a restricted fluid flow for dampening the movement between said members and said throttle.

8. A carburetor having a throttle barrel with a throttle pivotally mounted therein, a closed fluid container member, a wall member movable relative to said container member, a plurality of passage means having ditferent resistances to fluid formed in the wall of said container member for movement of fluid between opposite sides t of said wall member during relative movement between 30 said wall member and said container member, means connecting said throttle to one of said members, a movable element in said container member having spaced openings formed therein with an opening registrable with each of said passage means, a chamber having a movable member therein, and a mechanical connector between said movable member and said movable element, said movable member being responsive to an engine vacuum condition for moving said mechanical connector and said movable element in .a direction to select one of said passage means having a restricted fluid flow for dampening the movement between said members and said throttle.

9. A carburetor having a throttle barrel with a throttle pivotally mounted therein, a closed fluid container member, a wall member movable relative to said container member, a plurality of passage means having different resistances to fluid flow formed in the wall of said container member for movement of fluid between opposite sides of said wall member during relative movement between said wall member and said container member, means connecting said throttle to one of said members, a movable element in said container member having spaced openings formed therein with an opening registrable with each of said passage means, a chamber having a movable member therein, a passage connecting one side of said movable member to a source of manifold vacuum, and a mechanical connector between said movable member and said movable element, said movable member being responsive to manifold vacuum for moving said mechanical connector and said movable element in a direction to select one of said passage means having a restricted fluid flow for dampening the movement between said members and said throttle.

10. A carburetor having a throttle barrel with a throttle pivotally mounted therein, a closed fluid cylinder, a piston movable in said cylinder, a plurality of passage means having different resistances to fluid flow formed in the wall of said cylinder for movement of fluid between opposite sides of said piston during relative movement between said piston and said cylinder, means connecting said piston to said throttle, a tubular element around said piston having spaced openings formed therein with an opening registrable with each of said passage means, a vacuum chamber having a movable member therein, a passage connecting one side of said movable member toa source of engine vacuum, and a mechanical connectoribetween said movable member and said tubular elementand effective upon the attainment of a predetermined engine vacuum in said chamber to move said.

tubular element to a position to select one of said passage means having a restricted fluid fiowfor dampening the movement between said piston and cylinder and said throttle;

11. A multi-stage carburetor for an internalcombus tion engine comprising a body, primary and secondary induction passages formed through said body, primary and secondary venturis formed respectively within. said induction passages, primary and secondary throttle valves located respectivelyzwithin said induction passages and.

adapted to control the flow of combustible mixtures therefrom to the intake manifold of said engine, means for manually controllingrthe position. of said primary throttle valve, vacuum responsive actuatingmeans for controlling the position of said secondary throttle valve, saidvacuum' responsive means comprising a housing having a movable.

wall therein operatively connected to said secondary throttle valve and adapted to form a chamber in said housing, conduit means communicating between a source of venturi vacuum and said chamber, a closed fluid container, member, a wall member movable relative to said:

sponsive to an engine vacuum condition for selecting one of said passage means having a restricted fluid flow for" dampening the movement of'said secondary throttle valve as.determine'd'by said". actuating means.

12. A'multi-stage carburetor defined in .claim 11 where-' im'sa'idJsecond" means is responsive to engine-manifold vacuum for. selecting one QfJsaid passage means having 'a restricted fiui'd'flow':

' 1'3: Amulti-stagecarburetor defined in claim 1 1' Wherein' said'second means is responsive to'engine'governor vacuum for-selecting oneof 'said' passage means having a' restricted fluid flow;

' 14. A multi-stage carburetor defined in claim-11 wherein'said-first means connects said-vacuum responsive-ac-- tuating means to saidwall member.

15'. -Amulti-stage carburetor defined in claim 11 where-- insaid plurality ofpassage means is formed in said container member.

16." A' multi-stage-carburetor defined in:claim 11 where-- in resilient means is-provided in said chamber for urging said movable -wal1- 'in -a direction to close said-secondary throttle valve:

References Cited in thevfile of this patent UNITED STATES PATENTS 758020 Robinson Apr. 19,- 1904 1,318,749 Haeberlein Oct. 14, 1919 2,3'6716016 Olson- Jan; 16,1945 2,736,305 Kennedy Feb. 28, 1956 2,792-3915 Smith May 21, 1957 2,807,336 Sweeney Sept, 24, 1957 2,828,725 Hartzell Apr. 1, 1958 

